Casting freely oxidizable metal



, its object to provide a binder for green Patented Apr. 14, 1925.

UNITED STATES/PATENT OFFICE.

nAnonp H. OSBORNE, of" CLEVELAND, 0111b, ASSIGNO-R. 'ro AMERICANMAeNEsIuM CORPORATION, or NIAGARA FALLS, NEW,YORK\, A'coaronAnoN or NEWYORK.

(TASTING FREELY OXIDIZAIBLE METAL.

No Drawing.

To all whom it may concern:

Be it known that HAROLD H. OsBoRNE,"

a citizen of the, United States, residing at Cleveland, in the county ofCuyahoga and State of Ohio,'has invented certain new and usefulImprovements in Casting Freely Oxidizable Metals, of which the followingis a specification.

My invention relates to the casting of magnesium and high magnesiumalloys and other freely oxidizable metals and has for sand molds; i. e.,non-baked, which will not oxidize-the molten metal'when it comes incontact therewith, The ordinary binding material for green sand moldscontains water, but this cannot be used in casting magnesium and similarmetals due to the fact that the metal will oxidize when it comes incontact with the water. This has accordingly necessitated the selectionof a non-aqueous binder for such molds.

To be commercial, sand repared with such a binder must lift in theHasl-zs, part readily from itself and the pattern, shake freely from thecasting, leave the casting with a clean metallic surface and generallyproduce sound castings in the usual sense. In the repeated use of thebinding liquid it must not develop gumming fatty acids under the actionof the hot metal but must volatilize or form gases only.

In selecting such a binder, consideration must also be given to itsmolding qualities. In the use heretofore of other non-aqueous binders,such as heavy lubricating oils, the binding qualities depend largelyupon the viscosity and adhesiveness of the binder itself. lVhile the useof such a binder prevents burning of the metal, difliculty isexperienced in making the sand stick in the foundry flask and inmaintaining the shape of the mold.

I have discovered that glycerine not only prevents oxidation of themetal but also has desirable molding qualities. It mixes with the sandvery readily and, itsbinding action seems to come from the wettingof theclay in the sand, thus making available the natural binding propertiesof the clay, as in the case of water bound sand. Glycerine bound sandlooks and feelsvery much like water bound sand and in its molding actionbehaves very similar to water sand.

Application filed March 8, 1922. Serial No. 541,569.

One method of mixing and using glycerine sand is as follows: I The sandis heated until thoroughly dried and then while still warm, it is mixedwith anhydrous or nearly anhydrous glycerine, preferably dynamiteglycerine, in the proportions of about one pint of glycerine to fifteenor twenty pounds of dry sand. The proportion of glycerine and sand willof course vary with different grades of sand. sand have been completelyand thoroughly mixed, the mixtureis' allowed to soak for several hours,preferably over night, and it is then ready for use. From this point on,it is. molded and handled exactly as is water bound sand, except thatafter the castings into green m0lds, i. e. not baked, thus effecting agreat saving in time, fuel, labor and molding equipment. Its similarityto water and dimimilarity to oil in the manner in which it wets the clayof the sand, gives the sand the properties by virtue of which it can beformed into a mold which has all the properties that a mold should havein order to give satisfactory castings, i. e., suflicient strength tostand up and porosity to permit the venting of trapped or liberatedgases. It has permanency,.inthat after thesand has been mixed with theglycerine binder, there'is very little deterioration, except for thenecessity of the occasional addi- 'After the glycerine and tionofglycerine or glycerine rich sand to replace the glycerine whichhasbeen'dos't through volatilization and decomposltion and perhaps forthe necessity, at long intervals, of heating the sand for a while at amoderate temperature to drive off any moisture which the glycerine mayhave absorbed from the atmosphere because of its hygro- 70 are shakenout, the. sand is merely cut over and mlxed, and 1s then ready forsubsequent scopic nature. It chills the metal quiclrly andvolatilizescleanly in the mold leaving a dry layer of sand'therein.

physical and chemical properties to'glycerinc and accordingly may beused as equivalents therefor where their. price would permit.

In referring herein to anhydrous glycerine, it will be understood thaton account of the hygroscopic character of the compound, it will notalways remain absolutely water free; but the small amount of water whichit absorbs in this manner does not, howeverflm-aterially affect its use.

It will be understood therefore that although glycerine is the preferredbinding agent, I do not intend to so limit myself, but comprehend withinthe discovery those substances having similar properties to those ofglycerine, and properly falling within the scopeand'spirit of theappended claims.

1 claim: i

1. A'sand mold having a'binder cont-aim ing glycerine.

2. A green sand mold having a binder of substantially anhydrousglycerine.

3. A green sand mold having a binder containing a polyhydri alcohol.

4. The process of making a casting. of

freely oxidizable metal, comprising forming a mold from sand renderedmoldable by being mixed with a glycerine containing binder and castingsaid metal in said mold. 5. The process of making a magnesium or highmagnesium alloy casting comprising forming a inold from sand freed fromwater and rendered moldable by being mixed with glycerine and castingsaid metal in said mold.

'6. .The process of making a casting ofmagnesium and high magnesiumalloys which comprises forming a mold from sand with a binder containingglycerine and casting the molten metal in the said mold.

magnesium and high magnesium alloys which comprises formlng a mold fromsand with a substantially anhydrous liquid binder which increases themoldin -qualities of the sand by acting on the clay containing portionsto dBWBlOP its plasticity, and casting molten metal in the said mold,the said binder being volatilizable at the temperature of the moltenmetal.

9. The process of making a magnesium or high magnesium alloy castingwhich comprises pouring the molten metal into a sand mold having asubstantially non-aqueous binder which on being heated by the moltenmetal will give off gases which protect the magnesium from oxidation.

10. The process of casting freely oxidizable metals Which comprisespouring the molten metal into a mold containing a substance which onbeing heated by the molten metal will give-off gases which protect themetal from oxidation.

11. The process of casting magnesium and high magnesium alloys in sandmolds comprising mixing with the sand a substance which on being heatedby the molten metal will give off gases which protect the magnesium fromoxidation.

In testimony whereof I aflix -my signature.

HAROLD H. OSBORNE.

lVitnesse-s:

O. WILHELMY, V.- HOLZHAUE".

